直流微电网电压无静差与环流抑制策略研究

A New S strategy of Zero Steady-State Error Voltage Control and Circulating Current Suppression of the DC Microgrid

孤立直流微电网中,由于并联变换器所带负荷的波动与线路阻抗的不同,因此会存在直流母线电压降落和变换器间的环流问题。提出一种无源控制与PI控制结合的新型三闭环控制策略,以无源控制为电流内环,PI控制为中间电压环,线路阻抗补偿为最外环,既实现了对于扰动快速的无静差的跟踪,又有效的抑制由于线路阻抗不同而产生的并联变换器间的环流。为了验证所提出的控制策略,以两个BOOST变换器并联为例,在Matlab/Simulink中搭建仿真模型,将传统的无源控制与新型的控制策略进行比较分析,仿真结果表明,所提出的控制方法可以使电压无静差的跟踪负荷变化,而且基本消除了环流,最后,在RT-LAB的半实物仿真平台进一步验证了方法的有效性。

In an isolated DC microgrid, due to the different line impedance and load fluctuation of the parallel converter, there will be problems of circulating current between converters and voltage drop of DC bus.This paper proposes a new three closed-loop control strategy, which combines passive control with PI control.It consists of a current inner loop, intermediate voltage loop and line impedance compensation outer loop.It can not only track the disturbance quickly without static error but also effectively suppress the circulating current between parallel converters due to different line impedance.In order to verify the proposed control strategy, a parallel converter simulation model was built in Matlab/Simulink, the results of traditional PBC and new control strategy were compared and analyzed.The simulation results show that the proposed control strategy can eliminate the circulation and make the DC bus voltage stable when the load changes.Finally, the feasibility of the scheme is further verified in RT-LAB real-time simulation.